Typically, respiratory therapy is delivered in the form of a mask system positioned between a patient and apparatus providing a supply of pressurized air or breathing gas. Mask systems in the field of the invention differ from mask systems used in other applications such as aviation and safety in particular because of their emphasis on comfort. This high level of comfort is desired because patients must sleep wearing the masks for hours, possibly every night for the rest of their lives. In addition, therapy compliance can be improved if the patient's bed partner is not adversely affected by the patient's therapy and wearing of the mask generally.
Mask systems typically have a highly clinical aesthetic (as will be described below). This can lead to patients becoming embarrassed about their therapy since the clinical aesthetic serves as a blatant reminder that they are ill and consequently can leave a negative perception of the patient in the mind of an observer.
Mask systems typically, although not always, comprise (i) a rigid or semi-rigid portion often referred to as a shell or frame, (ii) a soft, patient contacting portion often referred to as a cushion, and (iii) some form of headgear to hold the frame and cushion in position. If the mask system does in fact include multiple components, at least some assembly and adjustment may be required, which can be difficult for patients who may suffer from lack of dexterity, etc. Further, mask systems often include a mechanism for connecting an air delivery conduit. The air delivery conduit is usually connected to a blower or flow generator.
Patient contacting portions, e.g., cushions, are typically constructed of a silicone material, but patient contacting portions including foam are known. For example, U.S. Pat. No. 5,429,683 discloses a lining for a mask made of a polyurethane foam covered with skin (e.g., latex or silicone). However, skinned foam does not allow the portion in contact with the face to breathe, which can lead to skin irritation, and the sealing portion may be subject to creasing which may cause discomfort and lead to leak. The skin can also feel too hard for some patients, depending on the thickness and support structure. The skin also does not allow a high degree of local deformation and may be subject to tension transfer across its surface, which can result in shifting of the mask on the face and loss of seal/comfort.
A range of mask systems are known including nasal masks, nose & mouth masks, full face masks and nasal prongs, pillows, nozzles & cannulae. Masks typically cover more of the face than nasal prongs, pillows, nozzles and cannulae. Nasal prongs, nasal pillows, nozzles and cannulae all will be collectively referred to as nasal prongs.
There is a continuous need in the art to provide mask systems with a high level of comfort and usability and a newly perceived need to provide mask systems having improved aesthetics (i.e., less clinical and bulky).